bool state_projectiont::is_new(const statet &state, bool use_cache)
{
// get the right map
assert(!state.data().previous.is_null());
state_listt &state_list=
state_map[state.data().previous_PC];
// first try syntactically
for(state_listt::const_iterator
it=state_list.begin();
it!=state_list.end();
it++)
if(is_syntactically_equal(*it, state))
return false; // not new
// now try expensive comparison
for(state_listt::const_iterator
it=state_list.begin();
it!=state_list.end();
it++)
if(is_equal(*it, state, use_cache))
{
// put into list anyways
state_list.push_back(state);
return false; // not new
}
// not found, it's new
state_list.push_back(state);
return true;
}
bool path_searcht::drop_state(const statet &state) const
{
// depth
if(depth_limit!=-1 && state.get_depth()>depth_limit) return true;
// context bound
if(context_bound!=-1 && state.get_no_thread_interleavings()) return true;
// unwinding limit -- loops
if(unwind_limit!=-1 && state.get_instruction()->is_backwards_goto())
{
for(path_symex_statet::unwinding_mapt::const_iterator
it=state.unwinding_map.begin();
it!=state.unwinding_map.end();
it++)
if(it->second>unwind_limit)
return true;
}
// unwinding limit -- recursion
if(unwind_limit!=-1 && state.get_instruction()->is_function_call())
{
for(path_symex_statet::recursion_mapt::const_iterator
it=state.recursion_map.begin();
it!=state.recursion_map.end();
it++)
if(it->second>unwind_limit)
return true;
}
return false;
}
void simulator_ctt::compute_goto_successors(
const statet &state,
queuet &queue)
{
const instructiont &instruction=*state.data().threads.front().PC;
unsigned count=0;
// must have target
assert(!instruction.targets.empty());
formulat instantiated_guard=
instantiate(state, 0, instruction.guard);
formulat new_guard_taken;
if(instantiated_guard.is_true())
new_guard_taken=state.data().guard;
else
{
new_guard_taken=formula_container.gen_and(
instantiated_guard,
state.data().guard);
formulat new_guard_not_taken=formula_container.gen_and(
formula_container.gen_not(instantiated_guard),
state.data().guard);
// do "guard is false" case
statet new_state=state;
new_state.data_w().threads.front().PC++;
new_state.data_w().guard=new_guard_not_taken;
new_state.data_w().taken=false;
new_state.set_previous(state, 0);
queue.add(new_state);
count++;
}
for(program_formulat::formula_goto_programt::
instructiont::targetst::const_iterator
t_it=instruction.targets.begin();
t_it!=instruction.targets.end();
t_it++)
{
statet new_state=state;
new_state.data_w().threads.front().PC=*t_it;
new_state.data_w().guard=new_guard_taken;
new_state.data_w().taken=true;
new_state.set_previous(state, 0);
queue.add(new_state);
count++;
}
if(count>=2) path_counter+=count-1;
}
void path_searcht::do_show_vcc(
statet &state,
const namespacet &ns)
{
// keep statistics
number_of_VCCs++;
const goto_programt::instructiont &instruction=
*state.get_instruction();
mstreamt &out=result();
if(instruction.location.is_not_nil())
out << instruction.location << "\n";
if(instruction.location.get_comment()!="")
out << instruction.location.get_comment() << "\n";
unsigned count=1;
std::vector<path_symex_step_reft> steps;
state.history.build_history(steps);
for(std::vector<path_symex_step_reft>::const_iterator
s_it=steps.begin();
s_it!=steps.end();
s_it++)
{
if((*s_it)->guard.is_not_nil())
{
std::string string_value=from_expr(ns, "", (*s_it)->guard);
out << "{-" << count << "} " << string_value << "\n";
count++;
}
if((*s_it)->ssa_rhs.is_not_nil())
{
equal_exprt equality((*s_it)->ssa_lhs, (*s_it)->ssa_rhs);
std::string string_value=from_expr(ns, "", equality);
out << "{-" << count << "} " << string_value << "\n";
count++;
}
}
out << "|--------------------------" << "\n";
exprt assertion=state.read(instruction.guard);
out << "{" << 1 << "} "
<< from_expr(ns, "", assertion) << "\n";
if(!assertion.is_true())
number_of_VCCs_after_simplification++;
out << eom;
}
void simulatort::explore(
const statet &state,
queuet &queue)
{
#ifdef DEBUG
std::cout << "simulatort::explore1\n";
#endif
#if 0
std::cout << "/////////////////////////////////////////////// "
<< "\n";
for(unsigned thread=0; thread<program_formula.threads.size(); thread++)
{
std::cout << "Thread " << thread << " Location: ";
if(state.data().PCs[thread]==
program_formula.threads[thread].formula_goto_program.instructions.end())
std::cout << "END" << std::endl;
else
{
instructiont &instruction=*state.data().PCs[thread];
std::cout << location_string(instruction.location) << std::endl;
}
}
std::cout << std::endl;
#endif
// dump it if the guard is false
if(state.data().guard.is_false())
return;
#ifdef DEBUG
std::cout << "simulatort::explore2\n";
#endif
if(history.check_history(
state, enable_qbf_cache, enable_small_history))
{
// we have seen it already
#ifdef DEBUG
std::cout << ">>>>>>>>>>>>>>>>>>>>>>>> SEEN ALREADY\n";
#endif
return;
}
#ifdef DEBUG
std::cout << "simulatort::explore3\n";
#endif
compute_successor_states(state, true, queue);
#ifdef DEBUG
std::cout << "simulatort::explore4\n";
#endif
}
void simulator_ctt::execute_assume(
statet &state,
const program_formulat::formula_goto_programt::instructiont &instruction)
{
formulat condition=
instantiate(state, 0, instruction.guard);
if(condition.is_true()) return;
// just add it to the guard
state.data_w().guard=
formula_container.gen_and(state.data_w().guard, condition);
}
void path_searcht::do_show_vcc(statet &state)
{
// keep statistics
number_of_VCCs++;
const goto_programt::instructiont &instruction=
*state.get_instruction();
mstreamt &out=result();
if(instruction.source_location.is_not_nil())
out << instruction.source_location << '\n';
if(instruction.source_location.get_comment()!="")
out << instruction.source_location.get_comment() << '\n';
unsigned count=1;
std::vector<path_symex_step_reft> steps;
state.history.build_history(steps);
for(const auto &step_ref : steps)
{
if(step_ref->guard.is_not_nil())
{
std::string string_value=from_expr(ns, "", step_ref->guard);
out << "{-" << count << "} " << string_value << '\n';
count++;
}
if(step_ref->ssa_rhs.is_not_nil())
{
equal_exprt equality(step_ref->ssa_lhs, step_ref->ssa_rhs);
std::string string_value=from_expr(ns, "", equality);
out << "{-" << count << "} " << string_value << '\n';
count++;
}
}
out << "|--------------------------" << '\n';
exprt assertion=state.read(instruction.guard);
out << "{" << 1 << "} "
<< from_expr(ns, "", assertion) << '\n';
if(!assertion.is_true())
number_of_VCCs_after_simplification++;
out << eom;
}
void goto_symext::symex_dead(statet &state)
{
const goto_programt::instructiont &instruction=*state.source.pc;
const codet &code=to_code(instruction.code);
if(code.operands().size()!=1)
throw "dead expects one operand";
if(code.op0().id()!=ID_symbol)
throw "dead expects symbol as first operand";
// We increase the L2 renaming to make these non-deterministic.
// We also prevent propagation of old values.
ssa_exprt ssa(to_symbol_expr(code.op0()));
state.rename(ssa, ns, goto_symex_statet::L1);
// in case of pointers, put something into the value set
if(ns.follow(code.op0().type()).id()==ID_pointer)
{
exprt failed=
get_failed_symbol(to_symbol_expr(code.op0()), ns);
exprt rhs;
if(failed.is_not_nil())
{
address_of_exprt address_of_expr;
address_of_expr.object()=failed;
address_of_expr.type()=code.op0().type();
rhs=address_of_expr;
}
else
rhs=exprt(ID_invalid);
state.rename(rhs, ns, goto_symex_statet::L1);
state.value_set.assign(ssa, rhs, ns, true, false);
}
ssa_exprt ssa_lhs=to_ssa_expr(ssa);
const irep_idt &l1_identifier=ssa_lhs.get_identifier();
// prevent propagation
state.propagation.remove(l1_identifier);
// L2 renaming
if(state.level2.current_names.find(l1_identifier)!=
state.level2.current_names.end())
state.level2.increase_counter(l1_identifier);
}
void goto_symext::operator()(
statet &state,
const goto_functionst &goto_functions,
const goto_programt &goto_program)
{
assert(!goto_program.instructions.empty());
state.source=symex_targett::sourcet(goto_program);
assert(!state.threads.empty());
assert(!state.call_stack().empty());
state.top().end_of_function=--goto_program.instructions.end();
state.top().calling_location.pc=state.top().end_of_function;
state.symex_target=⌖
state.dirty=new dirtyt(goto_functions);
assert(state.top().end_of_function->is_end_function());
while(!state.call_stack().empty())
{
symex_step(goto_functions, state);
// is there another thread to execute?
if(state.call_stack().empty() &&
state.source.thread_nr+1<state.threads.size())
{
unsigned t=state.source.thread_nr+1;
// std::cout << "********* Now executing thread " << t << std::endl;
state.switch_to_thread(t);
}
}
delete state.dirty;
state.dirty=0;
}
void goto_symext::vcc(
const exprt &vcc_expr,
const std::string &msg,
statet &state)
{
total_vccs++;
exprt expr=vcc_expr;
// we are willing to re-write some quantified expressions
rewrite_quantifiers(expr, state);
// now rename, enables propagation
state.rename(expr, ns);
// now try simplifier on it
do_simplify(expr);
if(expr.is_true())
return;
state.guard.guard_expr(expr);
remaining_vccs++;
target.assertion(state.guard.as_expr(), expr, msg, state.source);
}
void path_searcht::check_assertion(
statet &state,
const namespacet &ns)
{
// keep statistics
number_of_VCCs++;
const goto_programt::instructiont &instruction=
*state.get_instruction();
irep_idt property_name=instruction.location.get_property_id();
property_entryt &property_entry=property_map[property_name];
if(property_entry.status==FAIL)
return; // already failed
else if(property_entry.status==NOT_REACHED)
property_entry.status=PASS; // well, for now!
// the assertion in SSA
exprt assertion=
state.read(instruction.guard);
if(assertion.is_true()) return; // no error, trivially
// keep statistics
number_of_VCCs_after_simplification++;
status() << "Checking property " << property_name << eom;
// take the time
absolute_timet sat_start_time=current_time();
satcheckt satcheck;
bv_pointerst bv_pointers(ns, satcheck);
satcheck.set_message_handler(get_message_handler());
bv_pointers.set_message_handler(get_message_handler());
if(!state.check_assertion(bv_pointers))
{
build_goto_trace(state, bv_pointers, property_entry.error_trace);
property_entry.status=FAIL;
number_of_failed_properties++;
}
sat_time+=current_time()-sat_start_time;
}
void goto_symext::dereference(
exprt &expr,
statet &state,
const bool write)
{
// The expression needs to be renamed to level 1
// in order to distinguish addresses of local variables
// from different frames. Would be enough to rename
// symbols whose address is taken.
assert(!state.call_stack().empty());
state.rename(expr, ns, goto_symex_statet::L1);
// start the recursion!
guardt guard;
dereference_rec(expr, state, guard, write);
// dereferencing may introduce new symbol_exprt
// (like __CPROVER_memory)
state.rename(expr, ns, goto_symex_statet::L1);
}
void shared_accesst::rw_sets(
statet& state,
std::vector<bool>& is_shared,
std::vector<sharedt::sett>& reads,
std::vector<sharedt::sett>& writes)
{
unsigned nr_threads=state.threads.size();
reads.clear();
reads.resize(nr_threads);
writes.clear();
writes.resize(nr_threads);
is_shared.clear();
is_shared.resize(nr_threads, false);
if(state.atomic_section_count)
{
return;
}
sharedt shared(state);
unsigned current_thread=state.get_current_thread();
for(unsigned
thr=0;
thr<nr_threads;
++thr)
{
if(state.threads[thr].active)
{
state.set_current_thread(thr);
shared(reads[thr], writes[thr]);
is_shared[thr]=!(reads[thr].empty() && writes[thr].empty());
}
}
state.set_current_thread(current_thread);
}
bool state_projectiont::is_syntactically_equal(
const statet &old_state,
const statet &new_state)
{
if(old_state.data().guard!=new_state.data().guard)
return false;
unsigned v=0;
for(program_formulat::variablest::const_iterator
it=program_formula.variables.begin();
it!=program_formula.variables.end();
it++, v++)
{
if(it->is_global)
{
assert(v<old_state.data().globals.size());
assert(v<new_state.data().globals.size());
if(old_state.data().globals[v]!=
new_state.data().globals[v])
return false;
}
}
return true;
}
void simulator_ctt::execute_assert(
statet &state,
const program_formulat::formula_goto_programt::instructiont &instruction)
{
std::cout << "CHECKING ASSERTION\n";
formulat condition=
instantiate(state, 0, instruction.guard);
formulat property=
formula_container.gen_and(
state.data().guard,
formula_container.gen_not(condition));
// see if it is reachable
if(!property.is_false() &&
is_satisfiable(property))
{
tracet trace;
compute_trace(state, trace, true);
dump_trace(trace, instruction);
std::cout << "Assertion violated" << std::endl;
std::cout << std::endl;
error_state_found=true;
}
#if 0
else
{
// otherwise, treat this like an assumption
state.data_w().guard=
formula_container.gen_and(state.data().guard, condition);
}
#endif
}
void simulator_ctt::execute_assign(
statet &state,
const program_formulat::formula_goto_programt::instructiont &instruction)
{
statet new_state(state);
new_state.detatch();
for(program_formulat::assignst::const_iterator
it=instruction.code.assigns.begin();
it!=instruction.code.assigns.end();
it++)
if(it->in_use)
{
assert(it->variable<program_formula.variables.size());
new_state.data_w().set_var(
it->variable,
0,
instantiate(state, 0, it->value));
}
// do constraint
formulat instantiated_constraint=
instantiate(
state,
new_state,
0,
instruction.code.constraint);
new_state.data_w().guard=
formula_container.gen_and(
state.data_w().guard,
instantiated_constraint);
state.swap(new_state);
}
/// decide whether to drop a state
bool path_searcht::drop_state(const statet &state)
{
goto_programt::const_targett pc=state.get_instruction();
// depth limit
if(depth_limit_set && state.get_depth()>depth_limit)
return true;
// context bound
if(context_bound_set && state.get_no_thread_interleavings()>context_bound)
return true;
// branch bound
if(branch_bound_set && state.get_no_branches()>branch_bound)
return true;
// unwinding limit -- loops
if(unwind_limit_set && state.get_instruction()->is_backwards_goto())
{
for(const auto &loop_info : state.unwinding_map)
if(loop_info.second>unwind_limit)
return true;
}
// unwinding limit -- recursion
if(unwind_limit_set && state.get_instruction()->is_function_call())
{
for(const auto &rec_info : state.recursion_map)
if(rec_info.second>unwind_limit)
return true;
}
if(pc->is_assume() &&
simplify_expr(pc->guard, ns).is_false())
{
debug() << "aborting path on assume(false) at "
<< pc->source_location
<< " thread " << state.get_current_thread();
const irep_idt &c=pc->source_location.get_comment();
if(!c.empty())
debug() << ": " << c;
debug() << eom;
return true;
}
return false;
}
bool path_searcht::is_feasible(statet &state)
{
status() << "Feasibility check" << eom;
// take the time
absolute_timet sat_start_time=current_time();
satcheckt satcheck;
bv_pointerst bv_pointers(ns, satcheck);
satcheck.set_message_handler(get_message_handler());
bv_pointers.set_message_handler(get_message_handler());
bool result=state.is_feasible(bv_pointers);
sat_time+=current_time()-sat_start_time;
return result;
}
void simulator_ctt::execute_functioncall(
const statet &state,
edget &edge)
{
const program_formulat::formula_goto_programt::instructiont
&instruction=*state.data().threads.front().PC;
const irep_idt &function_id=instruction.code.function;
// find in program formula
program_formulat::function_mapt::const_iterator
f_it=program_formula.function_map.find(function_id);
assert(f_it!=program_formula.function_map.end());
const program_formulat::functiont &f=f_it->second;
// produce a start state
statet start_state(state);
statet::threadt &thread=start_state.data_w().threads.back();
// adjust PC
thread.program=&(f.body);
thread.PC=thread.start_pc();
// assign args
assert(instruction.code.function_args.size()==f.args.size());
for(unsigned i=0; i<f.args.size(); i++)
{
formulat formula=instruction.code.function_args[i];
formula=instantiate(state, 0, formula);
start_state.data_w().set_var(f.args[i], 0, formula);
}
std::cout << "Adding edge for " << function_id << std::endl;
// add edge
edget &f_edge=new_edge(function_id, start_state);
f_edge.calls.push_back(conft(edge, state));
}
void goto_symext::symex_decl(statet &state, const symbol_exprt &expr)
{
// We increase the L2 renaming to make these non-deterministic.
// We also prevent propagation of old values.
ssa_exprt ssa(expr);
state.rename(ssa, ns, goto_symex_statet::L1);
const irep_idt &l1_identifier=ssa.get_identifier();
// rename type to L2
state.rename(ssa.type(), l1_identifier, ns);
ssa.update_type();
// in case of pointers, put something into the value set
if(ns.follow(expr.type()).id()==ID_pointer)
{
exprt failed=
get_failed_symbol(expr, ns);
exprt rhs;
if(failed.is_not_nil())
{
address_of_exprt address_of_expr;
address_of_expr.object()=failed;
address_of_expr.type()=expr.type();
rhs=address_of_expr;
}
else
rhs=exprt(ID_invalid);
state.rename(rhs, ns, goto_symex_statet::L1);
state.value_set.assign(ssa, rhs, ns, true, false);
}
// prevent propagation
state.propagation.remove(l1_identifier);
// L2 renaming
// inlining may yield multiple declarations of the same identifier
// within the same L1 context
if(state.level2.current_names.find(l1_identifier)==
state.level2.current_names.end())
state.level2.current_names[l1_identifier]=std::make_pair(ssa, 0);
state.level2.increase_counter(l1_identifier);
const bool record_events=state.record_events;
state.record_events=false;
state.rename(ssa, ns);
state.record_events=record_events;
// we hide the declaration of auxiliary variables
// and if the statement itself is hidden
bool hidden=
ns.lookup(expr.get_identifier()).is_auxiliary ||
state.top().hidden_function ||
state.source.pc->source_location.get_hide();
target.decl(
state.guard.as_expr(),
ssa,
state.source,
hidden?symex_targett::HIDDEN:symex_targett::STATE);
assert(state.dirty);
if((*state.dirty)(ssa.get_object_name()) &&
state.atomic_section_id==0)
target.shared_write(
state.guard.as_expr(),
ssa,
state.atomic_section_id,
state.source);
}
void goto_symext::symex_step(
const goto_functionst &goto_functions,
statet &state)
{
#if 0
std::cout << "\ninstruction type is " << state.source.pc->type << '\n';
std::cout << "Location: " << state.source.pc->source_location << '\n';
std::cout << "Guard: " << from_expr(ns, "", state.guard.as_expr()) << '\n';
std::cout << "Code: " << from_expr(ns, "", state.source.pc->code) << '\n';
#endif
assert(!state.threads.empty());
assert(!state.call_stack().empty());
const goto_programt::instructiont &instruction=*state.source.pc;
merge_gotos(state);
// depth exceeded?
{
unsigned max_depth=options.get_unsigned_int_option("depth");
if(max_depth!=0 && state.depth>max_depth)
state.guard.add(false_exprt());
state.depth++;
}
// actually do instruction
switch(instruction.type)
{
case SKIP:
if(!state.guard.is_false())
target.location(state.guard.as_expr(), state.source);
state.source.pc++;
break;
case END_FUNCTION:
// do even if state.guard.is_false() to clear out frame created
// in symex_start_thread
symex_end_of_function(state);
state.source.pc++;
break;
case LOCATION:
if(!state.guard.is_false())
target.location(state.guard.as_expr(), state.source);
state.source.pc++;
break;
case GOTO:
symex_goto(state);
break;
case ASSUME:
if(!state.guard.is_false())
{
exprt tmp=instruction.guard;
clean_expr(tmp, state, false);
state.rename(tmp, ns);
symex_assume(state, tmp);
}
state.source.pc++;
break;
case ASSERT:
if(!state.guard.is_false())
{
std::string msg=id2string(state.source.pc->source_location.get_comment());
if(msg=="")
msg="assertion";
exprt tmp(instruction.guard);
clean_expr(tmp, state, false);
vcc(tmp, msg, state);
}
state.source.pc++;
break;
case RETURN:
if(!state.guard.is_false())
return_assignment(state);
state.source.pc++;
break;
case ASSIGN:
if(!state.guard.is_false())
symex_assign_rec(state, to_code_assign(instruction.code));
state.source.pc++;
break;
case FUNCTION_CALL:
if(!state.guard.is_false())
{
code_function_callt deref_code=
to_code_function_call(instruction.code);
if(deref_code.lhs().is_not_nil())
clean_expr(deref_code.lhs(), state, true);
clean_expr(deref_code.function(), state, false);
Forall_expr(it, deref_code.arguments())
clean_expr(*it, state, false);
symex_function_call(goto_functions, state, deref_code);
}
else
state.source.pc++;
break;
case OTHER:
if(!state.guard.is_false())
symex_other(goto_functions, state);
state.source.pc++;
break;
case DECL:
if(!state.guard.is_false())
symex_decl(state);
state.source.pc++;
break;
case DEAD:
symex_dead(state);
state.source.pc++;
break;
case START_THREAD:
symex_start_thread(state);
state.source.pc++;
break;
case END_THREAD:
// behaves like assume(0);
if(!state.guard.is_false())
state.guard.add(false_exprt());
state.source.pc++;
break;
case ATOMIC_BEGIN:
symex_atomic_begin(state);
state.source.pc++;
break;
case ATOMIC_END:
symex_atomic_end(state);
state.source.pc++;
break;
case CATCH:
symex_catch(state);
state.source.pc++;
break;
case THROW:
symex_throw(state);
state.source.pc++;
break;
case NO_INSTRUCTION_TYPE:
throw "symex got NO_INSTRUCTION";
default:
throw "symex got unexpected instruction";
}
}
bool match(
formula_containert &container,
const statet &state,
const std::map<vart, bool> &values)
{
// do the reset
container.reset_prop();
// build the SAT instance
satcheckt satcheck;
// 1st, the guard must hold
{
literalt l=state.data().guard.convert(satcheck);
satcheck.l_set_to(l, true);
}
#if 0
std::cout << "G: ";
state.data().guard.output(std::cout);
std::cout << std::endl;
#endif
// 2nd, the values must match
for(std::map<vart, bool>::const_iterator
it=values.begin();
it!=values.end();
it++)
{
const vart &var=it->first;
formulat f=state.data().get_var(var.var_nr, var.thread_nr);
literalt l=f.convert(satcheck);
satcheck.l_set_to(l, it->second);
#if 0
std::cout << "V: ";
state.data().values[v].output(std::cout);
std::cout << std::endl;
#endif
}
std::cout << "Running " << satcheck.solver_text() << ", "
<< satcheck.no_variables() << " variables, "
<< satcheck.no_clauses() << " clauses" << std::endl;
switch(satcheck.prop_solve())
{
case propt::P_SATISFIABLE:
// oh! match!
return true;
case propt::P_UNSATISFIABLE:
// nah, no match
return false;
default:;
assert(false);
}
assert(false);
return false;
}
void goto_symext::symex_decl(statet &state)
{
const goto_programt::instructiont &instruction=*state.source.pc;
const codet &code=to_code(instruction.code);
if(code.operands().size()==2)
throw "two-operand decl not supported here";
if(code.operands().size()!=1)
throw "decl expects one operand";
if(code.op0().id()!=ID_symbol)
throw "decl expects symbol as first operand";
// We increase the L2 renaming to make these non-deterministic.
// We also prevent propagation of old values.
const irep_idt &identifier=
to_symbol_expr(code.op0()).get_identifier();
const irep_idt l1_identifier=
state.rename(identifier, ns, goto_symex_statet::L1);
// prevent propagation
state.propagation.remove(l1_identifier);
// L2 renaming
unsigned new_count=state.level2.current_count(l1_identifier)+1;
state.level2.rename(l1_identifier, new_count);
// in case of pointers, put something into the value set
if(ns.follow(code.op0().type()).id()==ID_pointer)
{
exprt failed=
get_failed_symbol(to_symbol_expr(code.op0()), ns);
exprt rhs;
if(failed.is_not_nil())
{
address_of_exprt address_of_expr;
address_of_expr.object()=failed;
address_of_expr.type()=code.op0().type();
rhs=address_of_expr;
}
else
rhs=exprt(ID_invalid);
symbol_exprt l1_lhs;
l1_lhs.type()=code.op0().type();
l1_lhs.set_identifier(l1_identifier);
state.rename(rhs, ns, goto_symex_statet::L1);
state.value_set.assign(l1_lhs, rhs, ns);
}
// record the declaration
symbol_exprt original_lhs=to_symbol_expr(code.op0());
symbol_exprt ssa_lhs=original_lhs;
state.rename(ssa_lhs, ns);
target.decl(
state.guard,
ssa_lhs, original_lhs,
state.source);
}
void simulator_ctt::execute_instruction(
statet &state,
const program_formulat::formula_goto_programt::instructiont &instruction)
{
switch(instruction.type)
{
case GOTO:
assert(false);
// done somewhere else
break;
case ASSUME:
execute_assume(state, instruction);
break;
case ASSERT:
execute_assert(state, instruction);
break;
case ASSIGN:
execute_assign(state, instruction);
break;
case FUNCTION_CALL:
assert(false); // done somewhere else
break;
case OTHER:
assert(false);
break;
case SKIP:
case LOCATION:
case END_FUNCTION:
// do nothing
break;
case START_THREAD:
throw "start_thread is not supported";
break;
case END_THREAD:
assert(false);
break;
case ATOMIC_BEGIN:
state.data_w().in_atomic_section=true;
break;
case ATOMIC_END:
state.data_w().in_atomic_section=false;
break;
case DEAD:
break;
case RETURN:
assert(false); // done somewhere else
break;
default:
std::cerr << instruction.type << std::endl;
assert(false);
}
}
void simulator_ctt::execute_return(const statet &state, edget &edge)
{
// compute vector of return values
std::vector<formulat> return_values;
bool have_return=!state.data().threads.front().is_at_end();
if(have_return)
{
const program_formulat::formula_goto_programt::instructiont
&return_instruction=*state.data().threads.front().PC;
return_values.resize(return_instruction.code.assigns.size());
for(unsigned i=0; i<return_values.size(); i++)
{
formulat f1=return_instruction.code.assigns[i].value;
formulat f2=instantiate(state, 0, f1);
return_values[i]=f2;
}
}
// propagate to all call sites
for(callst::const_iterator it=edge.calls.begin();
it!=edge.calls.end();
it++)
{
const conft &conf=*it;
// save PC
const_targett PC=conf.state.data().threads.front().PC;
const program_formulat::formula_goto_programt::instructiont
&call_instruction=*PC;
// get return PC
PC++;
statet new_state=state;
// set PC to return location
new_state.data_w().threads.front().PC=PC;
new_state.data_w().threads.front().program=
conf.state.data().threads.front().program;
if(!call_instruction.code.function_lhs.empty())
{
if(have_return)
{
assert(call_instruction.code.function_lhs.size()==
return_values.size());
// do return value
for(unsigned i=0; i<return_values.size(); i++)
{
if(call_instruction.code.function_lhs[i].in_use)
{
unsigned lhs=call_instruction.code.function_lhs[i].variable;
new_state.data_w().set_var(lhs, 0, return_values[i]);
}
}
}
}
std::cout << "Adding to queue of " << conf.edge->function << std::endl;
// put it into the right queue
conf.edge->queue.add(new_state);
// make sure this is noticed
active_edges.insert(conf.edge);
}
}
